Einstein's statement that he thought V.'s ideas were "crazy" has been often
quoted out of context, but looking at V.'s memoir _Stargazers and Gravediggers_
and Einstein's papers, it is clear that Einstein regarded V.'s ideas as
"wild" (meaning, well off what people normally think of as scientific and
normal) but not at all impossible, considered objectively and looking at
the full range of physical possibilities. He had a number of semi-technical
discussions regarding _Worlds in Collision_ with Velikovsky.

The word Einstein used was "meshuggah", Yiddish or Hebrew for "crazy", used
humorously in some contexts to mean "offbeat" or "strange", but not literally
insane. It's the same use when Niels Bohr said that quantum mechanics was
so crazy, that it might be true.